NEW- COMPRESSION TEST RESULTS
after 4 cycles
1- 225
2- 225
3- 230
4- 235
5- 230
6- 235
7- 220
8- 235

That seems like a reasonable test as if all the cylinders had good compression. between the highest and lowest i see a 6% differance, but between the bank 1357 cylinders there is only a 3% diferance as well as the the 2468 cylinders


short history: Installed opti and new plugs (tr55s) (still had slight misfires after new opti install, later found out that the wires were arcing) , old one went out, drove about 500 miles, coming home going 30 mph and then i hear a few back fires and car dies. She starts but then dies after struggleing to stay alive, wont run very well. She would run for a few seconds and sometimes maybe up to 2 min and then die, missing all the time. I could rev her up and hold her for a sec then pop pop pop and she would almost die then i could recover her and then she would eventually die. I put new wires on because i saw some were arcing. Tried starting her up, misfireing like crazy and never really ran and then i saw smoke coming out of my intake. turned her off and pulled the plugs... every single one of them is black as crap and smell like gas.

What could be causing all my plugs to go so black? would the plugs be the couse of it not running? Can arcing wires cause fouled plugs? Or do i have a nother problem on my hand. In the morning i am goign to be doing a compression test.

 

Do a test on your coil. Make sure you don't have any of the plug wires mixed up. Are you positive you got the opti on correctly?

http://shbox.com/1/coil_testing.jpg

 

I replaced the coil and ICM and still no differance.

as far as the opti install goes.. the dowel pin goes into the notch that is the odd looking one of the 3... and i am sure i got that in there. I have gone through 4 (maybe 5) optis. I dont think it is that hard to install an opti but maybe i just keep screwing somehting up... i always follow write ups perfectly and i am a semi skilled mechanic i guess one could say.

 

did a compression test... results are on first post....

Compression looks good
Changed spark plug wires
Put a new Harness on
Changed Coil and ICM
checked leaky injectors (none leaked)
I know it is getting fuel i can see even where it came out the tail pipes
put my other pcm in and no differance

soooooo opti? and why am i blowing my optis ever 500-3000 miles?

 

I was thinking opti again. Did you check the length on your dowel pin? If it's too long you could be tearing the opti rotors up. I know when i got my LE2 cam i had to cut the dowel a good ways.

 

what should the length be... i think i read something like.62 of an inch.... how do i measure that?a nd also how do i cut it with out taking the cam out?

 

Before you start worring about cutting the dowel pin, pull the opti off and take it apart. If there are wear marks on the rotor or inside of the cap, then you have a problem. ~.65" is how long the pin should be. You might have to start probing the harnesses with a multimeter and making sure the harnesses or pcm isn't your problem.

 

Is it possible they are getting water or oil in them? I pulled my opti apart before installing it and the seal was total crap. Put a healthy does of silicone around the edges and sealed it up. Haven't had a problem even with a WP failure right above it.

 

I think i will try the silicone idea.... I would be absolutely amazed if it was y dowel length. I have never heard of a dowel length on an lt4 hot cam being wrong... only like on the comp cams or LE cams... but you never know, i am goign to be taking it all apart int he next couple of hours and will check the opti out and see if it is an oil/water prob.

 

Replaced the opti.... and all runs fine now.

thanks for all your help

 

What caused it to fail?

 

I win, but i hate when im right about optis

 

first off i bought it off a guy who said it only had like 5K on it... but after taking it off again it looked like it was sitting for 10 years, while taking it apart one bolt wouldnt even come loose so i ripped it open with my hands... the points on the cap had a white crusty corosion substance on them, some very badly and the rotor tip was green. The sensor wheel had a grove all in it like the dowel on the previous car was to long (i took apart another one of my old optis and didnt find the groove so i assume it was on there from earlier). So i assume that was the cause of the opti failure. I checked my cam dowel length, and i know people have stated it should be .62 inches on my car... well i have no clue wtheck is up with mine it is like .382 inches. Kinda short... but it runs. I measured it like 1000000 times and always the same. unless my caliper was off, but zeroed it in so it was on. Would a short pin ruin optis? i didnt even think it would work if it was to short.

 

I wouldnt think it would, if it was tooooo short then i dont think it would make contact with the opti good enough to spin it correctly. It may slip out and not stay in the correct hole. I think you'll be ok.

 

thats what i thought, but the pin on the old opti was in the right place still... so i guess i will see if i blow another opti, if so i am definetely lookin at a dyna spark.